Re: alfa-digest V7 #1162 Spica mods

[Tenney <proline@domain.elided>]

I alluded earlier to a "Spica mod" designed by Autodelta which was
contemporaneously available through ARI in the early '70's. Perhaps I
should have been more specific about the design concept and intended
application; it might have helped preclude some of the Digest dialog
between gullible "snake-oil" buyers and the qualified engineers who are
responding with irrefutable technological expertise. This has nothing to
do with the discussion of "which cars used which system and when...."

The Autodelta design - patterned after a Lucas one - completely replaced
the "logic" section of the Spica pump with a simple mounting boss within
which an ingeniously designed lever/cam was mounted. This component
resembled the number "6" with the "circular portion" providing a very
carefully designed cam profile and the "straight line" provided a lever
arm connected via pushrod to the throttle position bellcrank. The cam
face directly controlled movement of the rack (e.g. fuel delivery) and
was opposed by the rack return spring (the "weak link" in the design).
Once properly installed - and if every component worked as intended -
there was an absolutely direct and correct relationship between throttle
position (inlet air) and rack position (fuel delivery) without any
compromises as dictated by certification regulations or resulting from
deterioration within the logic section. Most of the Alfas using this
system successfully also used the "guillotine" type throttle bodies to
enhance inlet air flow.

Those of you who have driven race cars realize that *most* of the time
you are either using full throttle or full braking. The situation is
different for the "boy racers" among us whose Alfas must perform
adequately in a variety of applications and many of whom (for some
reason totally unfathomable to me) insist on using Spica systems that
have been (to put it delicately but correctly) bastardized by altering
the "logic" section to an "illogical" one with reference to the original
design (which so many profess to admire, respect and wish to
perpetuate). Are they "Spica-ing" with "forked tongues". I think so.
A correctly calibrated Weber or Dellorto setup would be far more
effective, reliable, inexpensive and (dare I say it?) "correct".

Names won't be mentioned here but every "cult" seems to have its own
"guru" - and the "modified Spica cult" is no different. With all due
respect to those involved, in the absence of new service parts (which
have been unavailable for years) any repairs, "restorations" or
"recalibrations" are totally dependent on cannibalizing other (used)
units. Any so-called "redesign" of *any* component within the Spica
logic section falls into the category of adding magnets to your fuel
lines in my opinion. I may be quite wrong on this but haven't seen any
dynamometer documentation to support the enthusiastic anecdotal reports
of post-modification improvements *exclusively* attributable to the
"re-engineered" Spicas. I would be *very* interested in seeing any such
documentation.

I guess "fiction" is more entertaining than "documentaries" and
anecdotal "endorsements" are more persuasive than the engineering
analyses being contributed to the Digest by some quite highly qualified
engineers currently working in areas allied to fuel systems and
combustion processes.

Alfas are good cars. Spica made good F.I. systems. Weber and Dellorto
made good carburetors. These manufacturers knew a hell of a lot more
about what they were doing (and had to do) to achieve their design
targets than most of us who use their products. Take your pick, take
proper care of it, and enjoy the results. As the old song lyric goes,
"Don't Mess With Mr. In-Between....."

My remarks and opinions are offered for informational purposes only
without any intent to impugn reputations or to generate acrimonious
debate. As always, I suggest you consider the source, the reliability,
and the motivational intent behind any information relating to your Alfa
that you may see on the Digest or allied internet "Homepages".

Best Regards,

Grinch

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